The Atlantic Ghost Crab (Ocypode quadrata) is a common inhabitant of sandy beaches along the southeastern United States coastline. These swift-moving crustaceans are abundant in the Myrtle Beach area and throughout the Grand Strand region of South Carolina. They are a frequent sight for beachgoers, particularly during the warmer months.
Identifying Ghost Crabs and Their Beach Habitat
The Ghost Crab is named for its pale, often grayish or straw-colored exoskeleton, which allows it to blend seamlessly with the dry sand. Their bodies are distinctly box-shaped, typically reaching a size of about 2 inches across the carapace at maturity. A distinguishing characteristic is their large, club-shaped eyestalks, which can swivel 360 degrees and fold down into a groove on the carapace.
Ghost Crabs inhabit the supralittoral zone, establishing their homes high up on the beach, above the daily high tide line. They excavate temporary burrows that serve as shelter from predators and daytime heat. The tunnels are typically deep, often extending up to 4 feet into the sand to maintain consistent temperature and humidity. A small pile of excavated sand often marks the entrance to an occupied burrow.
Common Behaviors and Activity Patterns
Ghost Crabs are primarily nocturnal, emerging from their burrows shortly after sunset to forage. Their tendency to appear and vanish quickly earned them the Latin genus name Ocypode, meaning “swift-footed.” They are fast runners, capable of achieving speeds of up to 10 miles per hour, making them one of the quickest invertebrates on the beach.
They are opportunistic scavengers, consuming a varied diet that includes small insects, clams, mole crabs, and general detritus washed up by the tide. While they are highly adapted to terrestrial life, they still possess gills and must periodically return to the water’s edge to moisten them. This behavior allows them to continue extracting oxygen from the air efficiently, as they cannot remain submerged for long periods without drowning.
After moistening their gills, the crabs use fine hairs on the base of their legs to wick water from damp sand up onto their gills through capillary action. This management of water is a significant adaptation for life in the harsh, dry environment of the upper beach. They may also store water in specialized chambers around their mouthparts to maintain the necessary humidity inside their underground home during the dry daytime hours.
Interaction and Safety Guidance
For beach visitors, the Ghost Crab poses virtually no threat to humans and is not considered an aggressive species. They attempt to flee quickly when approached, using speed and camouflage as their primary defense mechanism. They do not possess powerful claws that could cause significant harm, but they may pinch if handled or severely provoked. Responsible observation involves maintaining a respectful distance and avoiding interaction with the burrows, especially at night. Disturbing their habitat can disrupt their foraging or breeding cycles, negatively impacting the local population.